1. Field of the Invention
This invention relates to a device for monitoring the dispensing of drugs to a patient. More particularly it relates to such a device which detects in a positive manner the dispensing events.
2. Background Information
A variety of devices and methods have been described for controlling, noting, and keeping track of the dispensing of medicines to patients. These range from a simple nurse's hospital checklist system, to pill containers equipped with alarm clocks and the like and pill containers having timer-controlled latching devices which regulate the patient's access to medication. Some typical examples of these devices include the timed medication dispenser described by Roy J. Machamer in U.S. Pat. No. 4,382,688 which shows a medical dispenser having an electronic reminder to take the medication it contains. In this device the electronic reminder is disabled when the user takes the medication. In U.S. Pat. No. 4,448,541, Jonathan D. Wirtschafter describes a magnetically responsive switch device which is activated when a medication dispenser is opened so as to give an indication of the drug dispensing event. U.S. Pat. No. 4,367,955 of Donald H. Ballew shows a combined timer and container for dispensing medications wherein the container and its lid coact to initiate the timer cycle upon interengagement of the cap and container. U.S. Pat. No. 4,034,757 of Frederick F. Glover shows a fluid dispenser in which there are two switches which both must be activated simultaneously to provide an indication of drug dispensing. In the device a record is created listing dispensing events.
The foregoing patents are merely representative. Other background patents relating to medication dispensers include for example U.S. Pat. Nos. 3,369,697 of Glucksman et al.; 3,395,829 of Cogdell et al.; 3,651,984 of Redenbach; 3,722,739 of Blumberg; 3,762,601 of McLaughlin; 3,815,780 of Bauer; 3,911,856 of Ewing; 3,917,045 of Williams; 3,968,900 of Stambuk; 3,998,356 of Christensen; 4,207,992 of Brown; 4,223,801 of Carlson; 4,258,354 of Carmon et al.; 4,275,384 of Hicks et al.; 4,360,125 of Martindale et al.; 4,361,408 of Wirtschafter; 4,382,688 of Machamer; 4,419,016 of Zoltan; 4,448,541 Wirtschafter; 4,473,884 of Behl; 4,483,626 of Nobel; 4,490,711 of Johnston; 4,504,153 of Schollmeyer et al. and 4,526,474 of Simon.
The devices of the past which noted or kept track of drug dose delivery to the patient generally have sensed the dispensing of the doses inferentially. That is, they have sensed another event associated with the taking of a dose of drug and inferred as the result of the sensing of that event that the drug was in fact dispensed. As can be seen from the brief outlines provided above of some of the prior art patents relating to such devices, the devices may have noted the opening of the drug container via a trip switch or the like. Similarly, prior devices may have noted the inversion of the drug dose container or the like. Yet another approach has been to note the disruption of an electrical conductor as the pill is pushed out of a blister pack, or the like.
In each of these cases with prior art devices there is no direct measurement that the drug dosage has in fact actually physically been delivered to the patient requesting it. This can become a problem if discrepancies are discovered between the number of inferential signals detected and the number of pills actually dispensed. In situations such as in clinical trials or in the dispensing of drugs where the actual dosing pattern is sought, these failings of the devices of the art can add unwanted complexity and at times defeat the purpose of detecting the dose delivery. The present invention provides a device which solves the problems encountered with these devices of the art and gives rise to a more accurate record of the drug dispensing events.